System and method for evaluation using electron beam and manufacture of devices

Abstract

An electron beam apparatus having a longer life time of cathode, and allowing a plurality of electron beams to be arranged adequately around an optical axis and five or more electron beams to be formed from a single electron gun. The electron beams emitted from a cathode made of ZrO / W (tungsten zirconium oxide) or a cathode made of carbide of transition metal to the off-optical axis directions may be converged on a sample to scan it. The apparatus includes a plate for reducing a vacuum conductance defined between the electron gun chamber side and the sample side, and apertures are formed through the plate at locations offset from the optical axis allowing for the passage of the electron beams. In order to evaluate a pattern on the sample, the electron beam emitted from the electron gun is incident to the sample surface via an objective lens. The objective lens is composed of a flat electrode having an aperture centered on the optical axis and placed in parallel with the sample surface and an electromagnetic lens including a gap formed in a side facing to the sample. Further, in order to inspect a mask, spacing among a plurality of electron beams after having passed through the mask are extended by a magnifying lens and thus widely spaced electron beams are then converted into optical signal in a scintillator.

Description

BACKGROUND OF THE INVENTION [0001] The present invention relates to an electron beam apparatus, and in particular to an electron beam apparatus for evaluating a substrate (sample) having a minimum line width smaller than 0.1 μm with high throughput. The present invention further relates to an electron beam apparatus allowing a pattern on a wafer to be evaluated with high throughput and also to a pattern to be formed on the wafer with high throughput, even in a case that the wafer has a large diameter equal to or greater than 300 mmφ. The present invention further relates to a method for manufacturing devices using the same electron beam apparatus. [0002] The present invention relates to a method for evaluating a wafer or a mask having a minimum line width equal to or smaller than 0.1 μm used in manufacturing a semiconductor device with high throughput, and also relates to a method for manufacturing a device using the same method. The present invention also relates to a method for in...

AI Technical Summary

Benefits of technology

[0012] The present invention has been made in the light of the above-described problems of the prior art, and an object thereof is provide an electron beam apparatus allowing a cathode to have an extended life time without the negative effects of the ions generated in the optical column and a plurality of electron beams to be arranged adequately around the optical axis, and in some instances, allowing for a multi-electron beam consisting of five or more electron beams to be formed from a single electron gun. Another object of the present invention is to provide an electron beam apparatus allowing for the four electron beams to reach the sample without deteriorating the intensity of the beams and the electron beams of high current to be narrowed to a small diameter with a maximally suppressed space charge effect.

[0033] The present invention can provide a method for evaluating the pattern with higher beam resolution which is free from the problem of the misalignment of rotational position. The present invention overcomes the drawbacks associated with the prior art, and it can provide a method allowing for defect inspection of the mask with high throughput. According to the present invention, defect inspection of the mask can be achieved with high resolution. In the method for inspection of the present invention, since the LaB6 cathode is used in the space charge limited condition, the S / N ratio can be improved by four times as compared to that of the Schottky cathode, meaning that the same S / N ratio can be obtained with a beam current as low as 1 / 16. From the consideration of the availability of eleven to twenty-two beams, a throughput ten times as high as that of the prior art, or even higher, can be expected.

Problems solved by technology

A problem with the prior art is that every one of the above-described electron beam apparatuses suffers from an inherent problem, as will be described below.

That is, in the case of a minute-sized aperture having been formed on the optical axis allowing for passage of the electron beam, ions generated in a optical column downstream to the minute-sized aperture could pass through the minute-sized aperture to cause damage to the cathode.

Further, the case of forming a multi-beam from a single beam is also associated with a problem that if only as many as four electron beams can be formed, disadvantageously, the throughput in the pattern evaluation and / or the pattern forming will not be much improved.

Further, as for the ZrO / W cathode, the four electron beams emitted in the directions out of the optical axis, which are comparatively more intensive than the electron beam emitted in the optical axis direction, are unfortunately left unused.

On the other hand, as for the TaC cathode, although it can emit intensive electron beams, such intensive electron beams have not been utilized effectively.

Yet further, in the attempt to focus the highly intensive electron beams to make them narrower, problematically, the electron beams tend to be blurred from the space charge effect and unsatisfactorily focused.

Owing to this arrangement, there also exists a problem that distances from the coil to respective optical axes are varied, and consequently the lens intensity of the magnetic lens measured for the optical axis in a region proximal to the coil (i.e., the peripheral region) would be slightly different from the lens intensity for the optical axis in a region distant from the coil (i.e., the central region).

Another problem is associated with a case where the electron beams arranged in the matrix are used to carry out the pattern evaluation while continuously moving the sample table, as the areas subject to evaluation would be overlapped.

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